Compactifies maximal component of surface group representations into a closed ball.
problem Compactifying maximal component of surface group representations.
method Using cores of trees to study dynamics of mapping class group action.
result Boundary points geometrically described as mixed structures.
Diameters of ball intersections decrease as centers move apart.
problem Behavior of intersections of moving balls in Riemannian manifolds.
method Continuous decrease of intersection diameter as centers move apart.
result Diameter of intersections decreases continuously.
We obtain asymptotics of sequences of the holomorphic sections of the pluricanonical bundles on ball quotients associated to closed geodesics. A nonvanishing result follows.
Adding a point to configurations in closed balls depends on the number of points and their ordering.
problem When can a new point be added to configurations of n distinct points in a closed ball?
method Analyzes the conditions for adding a point based on the number of points and their ordering.
result The possibility of adding a point depends on the number of points and their ordering.
In a compact orbifold, for small prescribed volume, an isoperimetric region is close to a small metric ball; in a Euclidean orbifold, it is a small metric ball.
Compactness theorem for manifolds with scalar curvature and entropy bounds.
problem Understanding the structure of manifolds with specific curvature and entropy bounds.
method Using volume upper bounds to prove Gromov-Hausdorff closeness to Euclidean balls.
result Unit balls in such manifolds are bi-Hölder and bi-W1,p homeomorphic to Euclidean balls. Symplectic capacities of domains near balls are well-defined, but not for all C1-close domains.
problem Understanding symplectic capacities of domains near balls and their stability.
method General theorem about contact forms close to Zoll ones, spectral invariants for contact forms.
result Existence of minimizing geodesics in the space of contact forms.
The study explores conditions for a manifold to be a leaf of a complete foliation on the open unit ball.
problem Conditions for a manifold to be a leaf of a complete foliation on the open unit ball.
method Analyzes conditions for manifolds to be leaves of complete foliations.
result Provides answers to the question of when a manifold can be a leaf of a complete foliation on the open unit ball.
Small sub-Riemannian balls have diameter close to twice their radius.
problem Understanding the diameter of small sub-Riemannian balls.
method Analyzing C1,1 and C0 sub-Riemannian manifolds. result The diameter of small sub-Riemannian balls equals twice the radius in C1,1 manifolds, and is close to twice the radius in C0 manifolds. Stable capillary surfaces in weighted balls are disks.
problem Finding the shape of isoperimetric regions in weighted balls.
method Stability analysis and Hsiang symmetrization.
result Interior boundaries of isoperimetric regions in weighted balls are disks.
4-ball can be tiled with knotted surfaces.
problem Tiling the 4-ball with knotted surfaces.
method Using congruent knotted surfaces isotopic to the original surface.
result Tiling of the 4-ball with knotted surfaces.
In this note we provide natural optimal geometric conditions for a Riemannian manifold suitably covered by two open metric balls to be homeomorphic to a sphere. This can be viewed as a geometric analogue of Brown's theorem in topology stating that a closed manifold covered by two topological balls is a sphere.
Spaces of polynomials are shown to be Euclidean balls.
problem Understanding the geometry of Lorentzian and real stable polynomials.
method Refined connection between symmetric exclusion process and polynomial geometry.
result Spaces of Lorentzian and real stable polynomials are homeomorphic to closed Euclidean balls.
We obtain an improved pseudolocality result for Ricci flows on two-dimensional surfaces that are initially almost-hyperbolic on large hyperbolic balls. We prove that, at the central point of the hyperbolic ball, the Gauss curvature remains close to the hyperbolic value for a time that grows exponentially in the radius …
Article provides polytopes as dual unit balls of Thurston norms on 3-manifolds.
problem Understanding the dual unit ball shape of Thurston norms.
method Introduced a family of polytopes in Z^2g that can be dual unit balls of Thurston norms on 3-manifolds.
result Polytopes with mod 2 congruent vertices can be realized as dual unit balls of Thurston norms.
We prove that three spaces of importance in topological combinatorics are homeomorphic to closed balls: the totally nonnegative Grassmannian, the compactification of the space of electrical networks, and the cyclically symmetric amplituhedron.
New theorem shows shapes close to balls, flow converges to balls in 2D and 3D.
problem Understanding the asymptotic behavior of volume-preserving mean curvature flow.
method Proved a new quantitative Alexandrov theorem and used it to show flow convergence.
result Weak solutions of volume-preserving mean curvature flow converge to disjoint balls in R^2 and R^3.
This paper studies certain embedded spheres in closed affine manifolds. For n≥3, we investigate the dome bodies in a closed affine n-manifold M with its boundary homeomorphic to a sphere under the assumption that a developing map restricted to a component of ∂M^ is an embedding onto a strictly …
We show that under reasonable conditions, the spines of the handlebodies of a strongly irreducible Heegaard splitting will intersect a closed ball in a graph which is isotopic into the boundary of the ball. This is in some sense a generalization of the results by Scharlemann on how a strongly irreducible Heegaard split…
The paper proves the stability of a 3-ball under curvature constraints.
problem Stability of a 3-ball under L2-curvature pinching.
method Elementary computations based on Bochner formula and 2-spheres effective uniformisation result.
result The manifold is diffeomorphic to the Euclidean ball and metrically close to it.
We show that, the solutions of the isoperimetric problem for small volumes are C2,α-close to small spheres. On the way, we define a class of submanifolds called pseudo balls, defined by an equation weaker than constancy of mean curvature. We show that in a neighborhood of each point of a compact riemannian manifol…
Growth rate of Dehn twist lattice points in Teichmüller space is slower than mapping class group lattice points.
problem Analyzing the growth rate of Dehn twist lattice points in Teichmüller space.
method Comparing growth rates of Dehn twist, mapping class group, and multi-twist lattice points.
result The growth rate of Dehn twist lattice points is coarsely asymptotic to $e^{rac{h}{2}R}$, slower than the mapping class group.
Survey of rigidity and gap phenomena in sphere-ball submanifolds.
problem Rigidity and gap phenomena in submanifolds of sphere and ball.
method Comparison of techniques, pinching and gap theorems, Morse index and topology.
result Free boundary condition in ball forces stronger rigidity than in sphere.
New symplectic caps and embeddings found in complex projective plane.
problem Embeddings of homology balls in complex projective plane.
method Handlebody construction of symplectic caps and embeddings.
result First examples of symplectic handlebody decompositions of a closed symplectic 4-manifold.
Constructs minimal surfaces near the boundary of a ball.
problem Creating minimal surfaces close to the boundary of a ball.
method PDE gluing methods to construct FBMS of genus zero.
result Desingularizations of catenoidal annuli and flat discs near the boundary.
We construct non-trivial continuous isospectral deformations of Riemannian metrics on the ball and on the sphere in Rn for every n≥9. The metrics on the sphere can be chosen arbitrarily close to the round metric; in particular, they can be chosen to be positively curved. The metrics on the ball are both Diric…
Study minimal networks on spheres and balls near standard metrics.
problem Existence of minimal networks in spheres and balls with metrics close to standard.
method Finite-dimensional reduction method, inspired by configuration of networks and triods.
result Existence of minimal networks in spheres and balls for metrics close to standard.
The minimal number of critical points is studied for smooth functions on closed manifolds.
problem Determining the minimal number of critical points for smooth functions on closed manifolds.
method Investigates cylindrical ball neighborhoods and exotic critical points, proving the conjecture for certain types of critical points.
result The minimal number of critical points is the same for smooth functions without exotic critical points on closed manifolds of dimension at least 6.
If (Mn,g) is a closed Riemannian manifold where every unit ball has volume at most εn (a sufficiently small constant), then the (n−1)-dimensional Uryson width of (Mn,g) is at most 1.
If (M^n, g) is a complete Riemannian manifold with filling radius at least R, then we prove that it contains a ball of radius R and volume at least c(n)R^n. If (M^n, hyp) is a closed hyperbolic manifold and if g is another metric on M with volume at most c(n)Volume(M,hyp), then we prove that the universal cover of (M,g…
The paper divides minimal hypersurfaces in a ball into two parts.
problem Dividing minimal hypersurfaces in a ball into two parts.
method Analyzing hyperplanes and mean convex regions.
result Every hyperplane divides minimal hypersurfaces into two parts.
Smooth 4-manifolds have simple horizontal decompositions.
problem Classifying smooth, closed, orientable 4-manifolds.
method Horizontal handlebody decomposition.
result Simplest horizontal decompositions classify closed 4-manifolds.
The paper divides minimal surfaces in a ball into two parts.
problem Characterizing minimal surfaces in a ball with free boundaries.
method Analyzing planes and mean convex regions to divide surfaces and proving their properties.
result Every plane through the origin divides a minimal surface into exactly two parts.
Holomorphic foliations found in ball space with unique properties.
problem Finding holomorphic foliations in the ball space.
method Proving existence of nonsingular holomorphic foliations by closed complex hypersurfaces.
result First example of a holomorphic foliation with complete and incomplete leaves.
In this paper we prove that the unit ball B of C2 admits complete properly embedded complex curves of any given topological type. Moreover, we provide examples containing any given closed discrete subset of B.
Localized sum-of-norms clustering separates balls in data.
problem Clustering arbitrarily close data points in multivariate data.
method Localized sum-of-norms optimization for clustering.
result Proves a bound on clustering error in stochastic ball model.
We discuss closed symplectic 4-manifolds which admit full symplectic packings by N equal balls for large N's. We give a homological criterion for recognizing such manifolds. As a corollary we prove that CP2 can be fully packed by N equal balls for every N≥9.
We show if M is a closed, connected, orientable, hyperbolic 3-manifold with Heegaard genus g then g >= 1/2 cosh(r) where r denotes the radius of any isometrically embedded ball in M. Assuming an unpublished result of Pitts and Rubinstein improves this to g >= 1/2 cosh(r) + 1/2. We also give an upper bound on the volume…
Study shows Seifert fibered spaces don't bound rational homology balls.
problem Understanding when Seifert fibered spaces bound rational homology balls.
method Analyzes Seifert fibered spaces with different conditions and orientations.
result Characterizes conditions for Seifert fibered spaces to bound rational homology balls.
We prove the existence of extremal domains for the first eigenvalue of the Laplace-Beltrami operator in some compact Riemannian manifolds of dimension n≥2, with volume close to the volume of the manifold. If the first (positive) eigenfunction φ0 of the Laplace-Beltrami operator over the manifold is a nonconst…
In this paper, we prove uniform lower bounds on the volume growth of balls in the universal covers of Riemannian surfaces and graphs. More precisely, there exists a constant δ>0 such that if (M,hyp) is a closed hyperbolic surface and h another metric on M with $\area(M,h)\leq δ\area(M,hyp)$ then for every radiu…
Study geodesic structure of compact balls space and find explicit isometry.
problem Geodesic structure of space of compact balls.
method Investigate the shooting property to find explicit isometry.
result Explicit isometry between (Σ(X),dH) and XimesR≥0. The study finds at least 2 free-boundary minimal disks in convex 3-balls.
problem Finding minimal disks in convex 3-balls.
method Combining mean curvature flow, min-max theory, and degree theory.
result Existence of at least 2 free-boundary minimal disks in convex 3-balls for generic metrics.
The paper proves and analyzes Minkowski inequalities for nearly spherical domains.
problem Validating and stabilizing Minkowski inequalities for perturbed balls.
method Analyzing C1-perturbations of the ball, proving sharp and almost sharp inequalities. result Sharp geometric and almost sharp Minkowski inequalities for nearly spherical domains.
We construct pairs of conformally equivalent isospectral Riemannian metrics φ1g and φ2g on spheres Sn and balls Bn+1 for certain dimensions n, the smallest of which is n=7, and on certain compact simple Lie groups. In the case of Lie groups, the metric g is left-invariant. In the case of spheres a…
Study pinches eigenvalues and curvatures of convex hypersurfaces to make them nearly geodesic spheres.
problem Pinching eigenvalues and curvatures of convex hypersurfaces to understand their geometric properties.
method Pinching Heintze-Reilly's inequality via sectional curvature upper bounds.
result Closed convex hypersurfaces are Hausdorff close and almost isometric to geodesic spheres.
Dancing polygons and rolling balls linked via a special geometric distribution.
problem Understanding the geometric and mechanical relationship between dancing polygons and rolling balls.
method Mapping dancing polygons to trajectories of a rolling ball on a 3D surface, both described by a specific geometric distribution.
result Non-degenerate dancing pairs of polygons exist for all n≥6 and correspond to rolling ball trajectories. Given a closed subset $\La$ of the open unit ball B1⊂ℜn, n≥3, we will consider a complete Riemannian metric g on $\bar{B_1} \setminus \La$ of constant scalar curvature equal to n(n−1) and conformally related to the Euclidean metric. In this paper we prove that every closed Euclidean ball $\bar…